Testoderm TTS is a transcutaneous testosterone administration patch that can be applied to non-scrotal skin sites, such as the back, arm and upper buttocks areas. Prior studies have shown that the testosterone release rate in vitro increases with time. However, high in-vitro release rates may not result in high serum testosterone concentrations in patients because skin permeability is rate-limiting for drug absorption, even in the face of higher release rates. It is the purpose of this study to test whether such higher release rates present in preparations having a shelf age of >18 mos result in higher serum testosterone levels compared to preparations having a shelf age of <6 mos. This will be a multicenter study with a total enrollment of 28 hypogonadal men with the goal of having at least 24 men complete the study. We expect to enroll 8 -10 men in this center.